No size mentioned - fits similar to a modern medium or large (please see measurements below and use your own judgment, as sizing can be subjective)
Measurements:
Pit to pit - 20.5"
Pit to pit - 20.5"
Top of back of collar to bottom - 28"
Fantastic condition aside from a tiny snag near the bottom, as pictured. Barely noticeable but I'd rather mention it than not.